Non-linear response of an electrode–electrolyte interface impedance with the frequency

In this paper we analyze the frequency response of a distributed parameters non-linear circuit. This circuit is a fractal model of an electrode–electrolyte interface. The results show that the series equivalent resistance R_eq decreases as the number of fractal levels rises. Its frequency behavior is similar to the results described by other authors that used a constant phase angle element. At low frequency range, the series equivalent reactance X_eq decreases with frequency and R_eq shows a flat response in this range. The model also explains how interface geometry modifies the values of some electrochemical parameters. As roughness increases the Argand diagram shows smaller semicircles. The model behavior is like a single dispersion system with its central frequency increasing with the electrode roughness.     

单位球的Bergman空间上Schatten类加权复合算子

本文研究了单位球的Bergman空间上Schatten类加权复合算子,得到了这种加权复合算子属于Schatten-Von Neumann.理想S_p的几个充要条件.作为推论给出了Wφ,φ是一个Hilbert- Schmidt算子的充要条件是∫_(Bn)(|ψ(ω)|~2)/((1-|φ(ω)|~2)~(n 1)dV(ω)<∞..     

Catalytic Asymmetric Inverse‐Electron‐Demand Oxa‐Diels–Alder Reaction of In Situ Generated ortho‐Quinone Methides with 3‐Methyl‐2‐Vinylindoles

The first catalytic asymmetric inverse‐electron‐demand (IED) oxa‐Diels–Alder reaction of ortho‐quinone methides, generated in situ from ortho‐hydroxybenzyl alcohols, has been established. By selecting 3‐methyl‐2‐vinylindoles as a class of competent dienophiles, this approach provides an efficient strategy to construct an enantioenriched chroman framework with three adjacent stereogenic centers in high yields and excellent stereoselectivities (up to 99 % yield, >95:5 d.r., 99.5:0.5 e.r.). The utilization of ortho‐hydroxybenzyl alcohols as precursors of dienes and 3‐methyl‐2‐vinylindoles as dienophiles, as well as the hydrogen‐bonding activation mode of the substrates met the challenges of a catalytic asymmetric IED oxa‐Diels–Alder reaction.     

新烟碱类杀虫剂生物活性的理论研究和结构修饰*

在B3LYP/6-311G基组水平下,运用密度泛函理论(DFT)的量子化学方法,对20种重氮乙烷新烟碱类杀虫剂分子的电子结构特征进行了研究,获得了它们的前线轨道能(EHOMO、ENHOMO、ELUMO、ENLUMO等)、原子电荷(Qi)、摩尔熵(Sm)、偶极矩(μ)等量化参数与物理性质。经最佳变量子集回归研究发现,重氮乙烷新烟碱类杀虫剂分子对果蝇n AChRs、哺乳动物α4β2亚型的亲和力常数(p KD、p KA)分别与ELUMO、QW、QF、QN等参数具有良好的线性关系。逐一或逐四剔除交互验证以及VIF、tα/2检验,所建2个QSAR模型具有良好的稳健性及预测能力。根据2个QSAR模型推断了重氮乙烷新烟碱类分子可能的杀虫机理。进一步研究发现,在重氮乙烷新烟碱类分子的吡啶环上的合适部位,选用不含复键的吸电子能力较强的取代基团对其进行结构修饰,有利于提高修饰后分子的生物活性。基于分子17,设计出4种经结构修饰后对果蝇n AChRs亲和力显著提高的重氮乙烷新烟碱类分子(分别是分子27,28,30和31),希望能得到实验的证实。     

Effect of intercalating agents on structure and properties of dimer acid‐based polyamide modified by in situ doping of Na‐montmorillonite

Under the condition of 0.4% (mass), the effects of intercalating agents on conglomeration structure and thermal and mechanical properties of dimer acid‐based polyamide (DAPA) were investigated. The results show that layer‐stripped Na‐montmorillonite (MMT) with octadecyl trimethyl ammonium chloride caused a sharp decrease of content of the γ crystal phase in DAPA, thus bringing out decrease in mechanical properties and increase in IZOD notched impact strength while a sharp increase of content with the γ crystal phase in DAPA modified by Na‐MMT with dioctadecyl dimethyl ammonium chloride. Thus, it brought out a large increase in mechanical properties and a limited increase in IZOD notched impact strength. The decomposition reaction processes of DAPA modified by Na‐MMT and Na‐MMT with octadecyl trimethyl ammonium chloride were one step ranging from 410 to 500°C, respectively. The thermal decomposition reaction processes of DAPA modified by Na‐MMT with dioctadecyl dimethyl ammonium chloride were two steps. Copyright © 2016 John Wiley & Sons, Ltd.     

深部土高压卸载变形结构性量化参数确定及本构模型

用取自山东巨野矿区埋深300～600m的深部粘土样,在三轴伺服仪上进行原状和重塑土的高压三轴卸载试验,对比分析其变形特点;提出一种描述深部土高压卸载变形与强度连续变化的土结构性参数的方法,并根据三轴卸载试验结果,确定了巨野矿区深部土高压卸载变形结构性参数,建立了描述巨野矿区深部土高压卸载结构性本构模型。     

全断面隧道掘进机分类及其应用范围(英文)

目前,隧道掘进机的机械化及自动化水平得到了很大提高,隧道掘进机可以开挖不同的地质条件下各种形状的隧道。隧道掘进机的类型也越来越多,根据隧道工程场地所处的水文地质与工程地质条件,工程的使用特性及环境的限制,不同类型的隧道掘进机的工作机理需要进一步的理解并依此进行分类,以便选择合适的隧道掘进机。本文介绍了各种类型的全断面隧道掘进机的运行机理,并根据最终开挖隧道断面,掌子面的支护类型及岩土体的破碎机理对全断面隧道掘进机进行分类。本文也总结了各类型的隧道掘进机的应用范围。使用者可根据地质条件及特殊需要对隧道掘进机进行初步的选型。     

Protein‐Directed Solution‐Phase Green Synthesis of BSA‐Conjugated MxSey (M=Ag,Cd, Pb,Cu) Nanomaterials

Bovine serum albumin (BSA)‐conjugated M_xSe_y (M=Ag, Cd, Pb, Cu) nanomaterials with different shapes and sizes were synthesized in water at room temperature by a protein‐directed, solution‐phase, green synthetic method. The method features very low energy consumption and nontoxic reagents with high yields of concentrated nanoparticles. The obtained bioconjugated nanoparticles have good dispersibility, bioactivity, and biocompatibility. In addition, various functional groups of protein on the surface of the nanocrystals are suitable for further biological interactions or couplings, which is very important for further biological applications.     

Stability of the split-step backward Euler scheme for stochastic delay integro-differential equations with Markovian switching

In this paper, we concentrate on the numerical approximation of solutions of stochastic delay integro-differential equations with Markovian switching (SDIDEsMS). We establish the split-step backward Euler (SSBE) scheme for solving linear SDIDEsMS and discuss its convergence and stability. Moreover, the SSBE method is convergent with strong order γ = 1/2 in the mean-square sense. The conditions under which the SSBE method is mean-square stable and general mean-square stable are obtained. Some illustrative numerical examples are presented to demonstrate the stability of the numerical method and show that SSBE method is superior to Euler method.